This invention relates generally to bearings and, more particularly, to contact-type sealing structures for use in bearings of various types.
Various contact-type sealing structures have been provided in bearing assemblies to retain lubricant and to exclude debris and other contaminants. Such bearing assemblies may have a fabric or other "plain" type bearing liner or, alternatively, a plurality of rolling elements provided between an inner bearing ring and an outer bearing ring to facilitate free rotation of one bearing ring with respect to the other. The sealing structure closes a radial space between the inner bearing ring and the outer bearing ring at an axial end of the bearing assembly.
Typically, a contact-type sealing structure comprises a resilient seal lip fixed to one bearing ring and extending against the other bearing ring to effect a wiping action. However, if the inner and outer bearing rings of such bearing assemblies become "cocked" or otherwise misaligned, either during installation or during use, the resilient seal lip may be moved away from the surface of the opposed bearing ring. As a result, the sealing structure may fail to retain lubricant or may allow debris and other contaminates to enter the bearing.
Other problems may result from misalignment of the inner and outer bearing ring. The resilient seal lip may be moved toward the opposed bearing ring, causing damage to the sealing structure or to the opposed bearing ring. For example, if the resilient seal lip is mounted on a metal shield fixed to one bearing ring, the metal shield may be forced against the other bearing ring during misalignment. Such damage may occur at a point diametrically opposite a point where the resilient seal lip moves away from the opposed bearing ring, as described above.
The foregoing illustrates limitations known to exist in present contact-type sealing structures for bearings. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.